Lohan has been ordered to jail before—and for a probation violation. Last year, a judge slapped the actress with a 120-day sentence for flouting dual DUI charges. (Again, it all had to do with that jewelry store in Venice.) She was taken into custody but was immediately released on bail and ended up serving under house arrest instead.

The terms of her informal probation require that she obey all laws, or risk—yep—going back to the gray-bar hotel. And, of course, getting arrested for allegedly hitting and running means that somebody in authority suspects Lohan violated something.

But before Lohan would get sent back to the hoosegow, Los Angeles prosecutors would need to get involved, and ask judge to weigh in.

"All that would have to be proved is that there is probable cause to believe she broke a law, and then she would face a probation violation hearing," says criminal defense lawyer Troy Slaten (who's not involved in the Lindsay case). "At the hearing, the district attorney would have to prove by a preponderance of the evidence—meaning 'more likely than not'—that she broke a law.

"Then the judge could sentence her up to the max—I believe one year—with credit for time she has already served on that case."

Lohan could also negotiate with the local prosecutor if she thinks the odds are not in her favor.

And what are those odds? Well, the arrest is on the radar of the Los Angeles City Attorney's Office, but so far the prosecutors aren't showing their hand. "While this latest arrest in New York may have an impact on [Lohan's] probation," spokesman Frank Mateljan says, "we have not yet received any information from law-enforcement officials here or from NYPD. If or when we do, we will review for any potential action, but nothing has been discussed at this time."

In other words, watch this space. And keep an eye on the L.A. jails, too.